Sash-balance



(No Model.)

F. L. ROSENTRETER.

SASH BALANCE. 'No. 397,941. Patented Feb. 19, 1889..

WITNESSES." INVENTOR,

A TTOR/VEY.

N, versus, Fholo-Lflhngraphon Washinglnn. nv c UNITED STATES PATENT OFFICE.

FRANK L. ROSENTRETER, CLEVELAND, OI-IIO, ASSIGLOR, BY MESN E ASSIGNMENTS, TO \YM. H. CALDIVELL, OF ROCHESTER, NEIV YORK.

SASH-BALANCE.

SPECIFICATION forming part of Letters Patent No. 397,941, dated February 19, 1889.

Application filed February 3,1888. Elerial No. 262,886. (No model.)

To all whom it may concern:

Be it known that I, FRANK L. ROSENTRETER, a citizen of the United States, residing at Cleveland, in the county of Cuyahoga, State of Ohio, have invented certain new and useful Improvements in Spring Sash Balances, of which the following is a specification.

My invention relates to improvements in that class of window-sash balances in which the sash is supported at each side by a metal ribbon attached thereto and passing over and around a revolving spring-drum upon which it is wound, and the weight of the sash. supported by the action of a coil-spring within the drum, the drum being held at rest with the sash in any desired position by the action of a brake.

In thespriug sash-balances heretofore in use the retarding and restraining pressure of the brake has been applied either upon the outer coil of the ribbon wound upon the drum or else upon the narrow edges of the surface of the periphery of the drum on each side of the ribbon wound thereon. In the form er kind, as the sash is raised and the ribbon wound upon the drum, the pressure of the brake increases by reason of the increasing thicknesses of ribbon upon the drum under the brake, and the action of the brake to hold the drum and sash at rest is strongest when it is least needed 6., when. the coil-spring within the drum is partially uncoiled' and its action is weakest to move itwhile on the other hand as the sash is lowered and the ribbon unwound from the drum the pressure of the brake is diminished by reason of the decreasing layers of ribbon upon the drum under the brake, and the action of the brake to hold the drum and sash at rest is weakest when it is most needed-21 a, when the spring within the drum is most tightly coiled and its action is strongest to move it. In the latter kind the area of periphery surface to which the brake is applied is small and, the pressure is applied at right angles to its surface, by reason of which it is necessary to keep the brake-spring under strong tension in order to produce sufficient friction to hold the drum at rest and the sash in a required position, particularly when the drum-spring is tightly coiled and its action strongest. The result of a constant strong tension upon the hrake-spring is to weakel'l the spring, and the result of the strong pressure upon small frictional-surfaces is to Wear away the opposed surfaces of drum and brake,

.both these results making necessary frequent come these objections; to provide a springdrum and brake so shaped and fitted to each other that the necessary restraining action of the brake upon the drum can be produced with only a slight tension upon the spring, which presses the brake upon the drum, and thus secure for the brake-spring durability and uniformity of action without frequent adjustments, and also to secure a delicate adjustment or balancingof the rotating force of the drum-spring and the restraining action of the brake. I attain these objects by the mechanism illustrated in the accompanying drawings, in which- Figure l is a longitudinal vertical section of the whole device, and Fi 2 a cross-section of the drum and brake, similar letters referring to similar parts.

F is the frame which sustains all the parts in their proper relations.

D is a spring-drum fitted in the ordinary manner to be revolved in one direction by the coiled spring S within, one end of the spring being attached to the drum at or near its periphery, the other end being fixed to the stationary axis A, upon which the drum revolves and the ends of which axis are held by the frame 1 R is a ribbon of metal or othcrsuitable material for sustaining the sash, one end of the ribbon being attached to the edge of the sash and the other attached to the periphery of the drum in such manner that when the drum is revolved by the coil-spring within it the ribbon will be wound upon the drum and exert a lifting action upon the sa sh.

b b are two beveled portions of the sides of the drum near its periphery.

B is a brake provided with two lugs, L L, the inner surfaces of which are beveled to fit the two beveled surfaces upon the sides of the drum.

.9 is a spring fitted to press the brake against the drum, one end of the spring being attached loosely to the middle of the brake, the convex portion 0 of the springrestiug against the standard '1 and the lower end of the spring entering a screw-nut, N, through which passes the set-screw O, by turning which the tension of the spring 8 and the pressure of the lugs against the sides of the drum and the wedging-of the drum between the lugs may be increased or diminished.

The action of this brake is as follows: The action of the spring 3 presses the lugs L I against the two opposite sides of the drum in a direction )erpendicular to the periphery of the drum, but oblique to the two beveled surfaces, and the two beveled lugs embrace the beveled sides of the drum and clasp or grip the drum, which is thus wedged between them, so as to exerta strong retarding and restraining effect upon its revolution with but slight tension upon the brake-spring. The

pressure of the brake-sprin being applied to the middle of the brake, to which it is loosely attached, the pressure of the two ends of the brake upon the drum is thereby equalized.

For use in large windows and sustaining heavy sash, where an extra strong drum-spring is necessary, a secondary brake, b, may be added and caused by the spring 3 or any other convenient device to act upon the surface of the ribbon and exert a restraining effeet in addition to that of the principal brake upon the drum.

I-Iavin g fully described my invention, what I desire to claim and secure by Letters Patent In a spring sash-balance, the frame for sustaining the parts in their proper relations, the spring-drum and spring contained therein for rotating the same, and the sash-supporting ribbon attached to both drum and sash, in combination with a brake acting upon the sides of the drum and a secondary brake acting upon the ribbon, one of said brakes being actuated by an adjustable S1 )ll.1'lg, substantially as shown and described.

FRANK L. ROSENTRETER.

\Vitnesses:

J'As. J. HAvENs, W. H. SHUART. 

